Growth of early potatoes from different portions of seed tubers I. Emergence and plant stand

Several of the recently released early potato cultivars in Ontario are prone to poor and/or uneven stands. Studies were undertaken to investigate these problems. Basal seed halves of Jemseg and Yukon Gold were found to emerge an average of 4.6 and 5.7 days, respectively, later than shoots from apical halves or whole tubers in 3 years of study. No practical difference in emergence was found among tuber portions of Superior. Sums of squares attributed to seed portions accounted for 51.1 percent of the variation of days to 50 percent emergence for Jemseg, 50.3% for Yukon Gold and 8 percent for Superior. No difference in final percent emergence was found among the various seed portions of Jemseg and Superior. Cultivars with strong apical dominance or dormancy appear prone to uneven emergence.